In the prior art, there has been implemented in practice a disk recording device which encodes a television broadcast in an analog format, or a video signal which has been recorded upon a VHS tape in an analog format, into a digital format, and records it upon a disk. As a user requirement for such a disk recording device, it is desired to perform video recording at as high a picture quality as possible, with the overriding stipulation that the contents which are desired to be video recorded upon the disk (in other words, for which it is desired to record a video signal upon the disk) should fit upon a single disk without overflowing therefrom. In order to meet this requirement, there has been disclosed (refer to Japanese Laid-Open Patent Publication Heisei 9-284715 and Japanese Laid-Open Patent Publication Heisei 10-92106) a disk recording device which, when performing video recording, sets the bit rate for encoding according to the picture quality and the video recording time period, and performs recording according to this bit rate. Furthermore, in the section “Background Art” of Japanese Laid-Open Patent Publication Heisei 9-284715, an implementation is described in which, during recording with a video tape recorder, the video recording is changed over, in time division, between a standard mode and an extended time video recording mode in which the picture quality is reduced.
However, with the techniques described in Japanese Laid-Open Patent Publication Heisei 9-284715 and Japanese Laid-Open Patent Publication Heisei 10-92106, it is not easy to set the bit rate individually according to the picture quality and the video recording time period, and there has been the problem that the program for performing this setting becomes complicated. In order to avoid this, in prior art devices, a plurality of bit rates are provided in steps. Since with prior art devices recording must be performed in one or the other of these video recording modes, accordingly sometimes recording has been performed at a bit rate reduced by one step (in other words, by reducing the picture quality), even if quite a large amount of space still remains upon the disk.
Furthermore, the embodiment of the VTR described in Japanese Laid-Open Patent Publication Heisei 9-284715, only offers a simple combination of two video recording modes, and no specific method of combining them is disclosed. But there may be a problem of poor picture quality, depending upon the way in which the two video recording modes are combined.
In consideration of this type of problem, the present invention takes it as its object to provide a disk recording device which enhances the picture quality during video recording, while employing a simple method of controlling the bit rate, and while preventing any spillage over from a single disk of the contents which are desired to be recorded.